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Departments | Conservation | In the News | Workers add color to county roads - April 21, 2007

Workers add color to county roads

Article written by Randy Miller and used with permission from the Globe Gazette, published on Saturday, April 21, 2007.

 

With spring approaching, Cerro Gordo County Conservation Board roadside biologists are preparing for work on the newest additions to the growing number of roadsides that have been seeded to native vegetation.

 

Prior to any restoration, the right-of-way must be prepared to maximize its potential as a prairie restoration site. Preparation efforts may begin in the fall with the burning of existing vegetation. This allows for an early, uniform re-greening of the right-of-way in the spring. Once this vegetation is 6 to 10 inches tall, it is sprayed with a non-selective herbicide (glyphosate). Spraying existing vegetation eliminates the competition for newly planted native seed.

 

If fall burns are not a viable option, existing vegetation is mowed (if necessary) and sprayed in the spring prior to seeding. Mowing the right-of-way reduces the vegetation to a height that allows sunlight to reach soil level.

 

So when do we actually plant the native vegetation? Most native species germinate when the soil temperature reaches a range of 50 to 60 degrees F. We try to plant the seed before the soil temperature reaches 50 degrees. As soil temperatures rise, the seeds germinate, and plant growth ensues.

 

For a spring planting, it is important to allow the native seed at least six weeks to develop root systems prior to hot, dry summer weather. Planting the seed before the soil temperatures reach 50 degrees usually ensures a developing plant enough growth time to survive the summer. Of course, working in right-of-ways may mean waiting until the roadside is dry enough for our equipment to operate properly, so timing is often dependent on seasonal spring weather.

 

Another planting option is seeding roadsides in the fall. For fall plantings we must wait until the soil temperature falls below 50 degrees before planting the native seed. The prairie seed will lay dormant during the fall and winter, and then begin to grow the following spring when soil temperatures reach the seed's germination range.

 

How do we plant the native vegetation? By using equipment specially designed for planting native seed. One such piece of equipment is our native seed drill. Most of our restoration sites have been planted using this piece of equipment. Native seed is extremely valuable, and we do not want to waste any of it. Conversely, we also need to make sure that we are putting enough seed into the ground. The drill can be calibrated to suit a given seed mix and ensure that we are planting the necessary amount (measured in pounds of seed per acre).

 

It is also important to plant prairie seed at the proper depth. Most native species cannot emerge when planted into the soil deeper than a half inch. So setting the drill at approximately 1/8 to 1/4 of an inch is also important. Using the drill ensures proper seed depth and the confidence of knowing we are planting the right amount of seed.

 

An additional method of planting native prairie seed is distributing it using our broadcast seeder. This is a new piece of equipment purchased using money from the Living Roadway Trust Fund Grant. Broadcast seeding "throws" seed behind the applicator, eliminating rows associated with native drills. Broadcasting can also seed larger areas quickly because it can seed a 30- to 40-foot path in one pass. However, employing this method requires more soil preparation work compared to using a seed drill because broadcast seeders work best when the prairie seed is spread over bare soil. This requires that a given site must first be cultivated, and then re-emerging vegetation sprayed. Once re-emerging vegetation is under control, we broadcast the prairie seed and run a culti-packer over the site to ensure proper seed to soil contact.

 

The final method we use is hydroseeding, which is effective for re-vegetating roadsides that have been "cleaned out" or re-sloped for drainage purposes by the Secondary Roads Department. Cool season grasses, a quick growing cover crop (such as oats), and native prairie seed is combined with water in the hydroseeder.

 

Cool season grasses and a cover crop are used to get fast growing vegetation into the roadside to stabilize the slopes of the ditch as quickly as possible. Shredded recycled newspaper is added to the mixture to create a thick slurry, which helps reduce erosion and acts to hold in moisture for the seed. The slurry/seed mixture is dispersed on the roadside under pressure, using specialized nozzles that accomodate for differing types of ditch.

 

Roadsize biologists have been re-estabilishing native prairie sites throughout the county for nearly two decades. Roadside prairies offer a diversity of plant life and color not seen in a typical Iowa roadside. These restorations are not only beautiful, but also highly valuable to a wide variety of wildlife in the area.

Cerro Gordo County Conservation Office